1. Field of the Invention
The present invention relates to a digital measuring device, and in particular to a measuring device applicable to digital measurement of a torque for tightening a tire valve core, a tire pressure, or a tire tread depth and having functions of digital computation, displaying, and alarm issuing.
2. The Related Arts
A conventional tire valve stem comprises a valve core, which is a core and a vital component of the tire valve stem and is often mounted and dismounted by applying an assembling/disassembling tool. In using a known assembling/disassembling tool to mount/dismount a valve core, if the torque used to carry out a loosening or tightening operation is not properly controlled, a potential risk of air leaking from a tire or damaging the tire valve stem may result. For example, when the valve core assembling/disassembling tool does not apply a sufficient torque to mount and securely fix a valve stem, air leaking from the tire may occur later. If the valve core assembling/disassembling tool applies an excessive torque to mount a valve stem and makes the valve stem over-tightened, the thread of the valve core and the valve stem may undergo excessive abrasion and may get broken, leading to an undesired situation of replacing the entire valve stem. Similar problems of excessive abrasion or breaking of the threads of the valve core and valve stem may also occur in dismounting the valve core using the valve core assembling/disassembling tool.
Prior art documents in this field are known, such as Taiwan Utility Models M469205, which discloses a valve stem removing tool; M464346, which discloses an improved structure of a tool for removing a valve stem of a tire; M341613, which discloses a valve core removing member for mounting/dismounting an internal valve component of a tire valve stem; M340369, which discloses a pulling device for tire valve stem; US Patent Publication No. 2013333769, which discloses a “combination tire valve core removal and fluid fill tool”; PCT application No. WO2005115685, which discloses a “universal vehicle tire valve core and cap removal and installation tool”, and French patent application No. 2880295, which discloses an inflatable tire's valve core dismounting tool, which has a dismounting unit comprising a rod with a pin that is supported against an extension of a plug when a core is released, where the extension extends within a body comprising a filtering unit and perforations. These prior art documents discloses various types or typical arrangements of known valve stem mounting/dismounting tool. However, these devices or tools all suffer the same long-existing problems and drawbacks of the prior art that when the device or tool is used by a user to mount or dismount a valve stem, it may potentially have the valve stem under-tightened, leading to a potential risk of air leaking, or it may have the valve stem over-tightened, leading to excessive abrasion or even breaking of the threads of the valve core and valve stem, making it necessary to replace the entire tire valve stem.